The invention relates to a method for transporting, checking, filling and sealing a bag which is comprised of a bag body that can be spread out to form a rectangular cross section, said bag body being made up of two wider first and two narrower second bag walls, a bag bottom sealing the bag body at the bottom, a bag opening bordering the bag body at the top, and an opened bag seal, whereby the bag seal itself comprises first sealing flaps which are connected to the first bag walls respectively and stick out horizontally from the bag opening outwards, and towards the first bag walls at right angles, second sealing flaps which are connected to the second bag walls respectively and which liexe2x80x94especially when folded inwards onto the bag openingxe2x80x94horizontally so that the first sealing flaps and the second sealing flaps form a frame-shaped sealing collar lying on a horizontal level.
The bag is designed in particular to be filled with pulverized filling products. The process of filling pulverized filling products into bags and the subsequent sealing of the bag seals brings to light several problems which will be covered in the following. In this connection, particularly for paper bags, hot melting glue is usually applied to the sealing surfaces for the purpose of sealing, and glued together or, in the case of bags made from thermoplastic foils, sealing surfaces lying on top of each other are thermally welded together.
One problem is presented by the formation of dust which is difficult to suppress during the filling process leading to the soiling of the plant and working place stress and even to the risk of dust explosions. This formation of dust must therefore be kept as low as possible.
In order to keep the formation at a bearable level valve bags are widely used in which a valve sleeve is glued in one end of a cross bottom element. The disadvantage of such bags lies in the reduced filling speed which is limited by the valve cross section in which a filler neck with a diameter of few centimeters is integrated. In addition the manufacturing and recycling is more costly due to the use of additional valve sleeves.
When open-mouthed bags are being used the filling speed can be increased however the entire sealing surfaces are dust covered after the filling process so that the sealing is not always effected faultlessly.
A second problem lies in the fact that the area of the bag seal is inevitably covered by a layer of dust. A dust covered surface impedes the gluing process using hot melting glues as well as the welding of the surfaces of thermoplastic foils.
A further problem arises in that bags filled with pulverized filling products which are sealed after the filling process for example by folding over, have micro openings at the folding corners which in turn are connected to the bag interior via channels out of which filling products can spill and through which insect pests can gain access especially in the case of food stuffs.
This being the basis it is the aim of the present invention to provide a method for transporting, testing, filling and sealing a bag which can be conducted with a most extensive suppression of formation of dust and allows a sealing of the bag which is not influenced by the formation of dust.
The solution for this lies in the properties of the independent procedure and device claims. These are based on a bag which is comprised of a bag body that can be spread out to form a rectangular cross section, said bag body being made up of two wider first and two narrower second bag walls, a bag bottom sealing the bag body at the bottom, a bag opening bordering the bag body at the top, and an opened bag seal, whereby the bag seal itself comprises first sealing flaps which are connected to the first bag walls respectively and stick out horizontally from the bag opening outwards, and towards the first bag walls at right angles, second sealing flaps which are connected to the second bag walls respectively and which liexe2x80x94especially when folded inwards onto the bag openingxe2x80x94horizontally so that the first sealing flaps and the second sealing flaps form a frame-shaped sealing collar lying on a horizontal level. A preferred embodiment and method for manufacturing such a bag is described in the patent application of Chronos Richardson GmbH lodged at the same time. An essential feature of the aforementioned method is the fact that the first sealing flaps are held in place by propelling conveying means during transport, testing, filling and sealing of the bag so that the bag can be kept suspended freely by these. This applies especially to the filling of the bag. Inside the transport means which is particularly comprised of conveyor belt pairs, guide profiles or guide beads can support the parts of the aforementioned sealing collar which are positioned horizontally.
A procedure and a device for testing a bag stands out because of the fact that the flattened bag body is kept in its flattened shape betweep large-surface air permeated angle brackets and that a pressure joint is tightly put onto the essentially horizontally positioned sealing collar with a clearance to the bag opening whereby compressed air is supplied for test purposes via the bag openings. If an excessive pressure drop occurs at the pressure joint the first sealing flaps will be released by the transport means and the faulty bag is ejected.
A new method and a special apparatus for filling operations are characterized by a filler neck which has sealing compounds running along the edge of the bag opening enclosing the opening which are placed on the sealing collar being positioned essentially horizontally before the filling products are transferred into the bag. Therefore the sealing collar is kept free of filling products and especially dust for the purpose of a later sealing process. A special procedure and a corresponding apparatus for sealing the filled bag in the first step is characterized in that a cover sheet which is to be glued onto the area previously kept dust free by the filler neck, or welded to the sealing collar, is placed on the essentially horizontal sealing collar. In this connection it is also essential that the sealing collar lies on a plain surface whereby a cover sheet having been placed for example in such a way that it can be unrolled, or in a level configuration, is xe2x80x9csealedxe2x80x9d circumferentially with the dust free area.
The final folding of the bag seal can be effected in further steps using further sealing devices.
In the following details of the devices and the method according to the invention are described in more detail using the description of embodiments.